Canada has become the first country to announce it will officially pull out of the Kyoto accord on reducing greenhouse gases.

Canadian environment minister Peter Kent said it was not economically feasible for Canada to continue under the rules of the Kyoto agreement in 2012.

He made the announcement two hours after returning to Ottawa from the climate talks in Durban, where countries agreed to extend Kyoto for five years and hammer out a new deal forcing all big polluters for the first time to limit greenhouse gas emissions.

Canada, a major energy producer which critics complain is becoming a climate renegade, has long complained Kyoto is unworkable precisely because it excludes so many significant emitters.

"As we've said, Kyoto for Canada is in the past ... We are invoking our legal right to formally withdraw from Kyoto," Mr Kent told reporters.

He said the decision would save the government $14 billion a year in penalties and blamed what he called an incompetent Liberal government that signed the accord but then took little action to make the necessary emissions cuts.

"To meet the targets under Kyoto for 2012 would be the equivalent of either removing every car, truck, all-terrain vehicle, tractor, ambulance, police car and vehicle off every kind of Canadian road," Mr Kent said.

He said the Kyoto accord was "an impediment" to finding a real solution to climate change because it does not include the world's largest emitters, China and the United States.

'National disgrace'

Environmentalists quickly hit out against the move.

"It's a national disgrace. Prime Minister [Stephen] Harper just spat in the faces of people around the world for whom climate change is increasingly a life-and-death issue," said Graham Saul of Climate Action Network Canada.

Mr Kent did not give details on when Ottawa would pull out of the treaty.

Canada kept quiet during the Durban talks so as not to be a distraction, he added.

"The writing on the wall for Kyoto has been recognised by even those countries which are engaging in a second commitment," he said.

Kyoto's first phase was due to expire at the end of 2012 but has now been extended until 2017.

Mr Kent said Canada would work towards a new global deal obliging all major nations to cut output of greenhouse gases.